Thin Film Transistor-Liquid Crystal Display (TFT-LCD) has been widely used of various applications in flat panel display field due to characteristics of low radiation thin thickness and low power consumption, etc. Most of desktop TFT-LCD devices are based on twisted nematic (TN) mode. However, the first electrode and the second electrode of traditional TN mode LCD device are separately formed on an upper substrate and a lower substrate, and liquid crystal (LC) molecules sandwiched between the upper substrate and the lower substrate rotate in the plane orthogonal to the two substrates. Due to the optical anisotropy of the LC molecules, optical paths are different after light beams pass through the LC molecules from different angles and enter human eyes. Therefore, optical path difference reliably causes different display effects at different viewing angles.
In order to solve or overcome the problem of viewing angle variation caused by the optical path difference, a method of adding compensation films in a TN mode LCD device is generally used to improve the viewing angle, due to the lower requirement of viewing angle in a personal and working environment. However, some products such as television, handheld personal digital assistant (PDA) have higher viewing angle requirement. Therefore, some new improved LCD modes, such as multi-domain vertical alignment (MVA) mode, optically compensated bend mode, fringe field switching (FFS) mode, in-plane switch (IPS) mode, and other wide viewing angle technologies have been developed and applied to relevant products.
Because the technical threshold is low, the method of adding compensation films in the TN mode LCD device is broadly applied. However, due to the compensation film having singular definite optical property, the compensation film cannot compensate an arbitrary viewing angle at an arbitrary gray level. Therefore, an inherent gray level inversion phenomenon of the TN mode LCD device still exists.
Due to employing negative LC material and protuberance structure or complex electrode arrangement, a response time of an MVA mode LCD device is long, and a manufacturing process of the MVA mode LCD device is complicated. Furthermore, a vertical alignment (VA) mode LCD device is liable to generate serious mura effect when being touched, and is thereby unsuited to be combined with touch technology.
Even though an Optically Compensated Bend (OCB) mode LCD device has inherent optical self-compensation effect and high response speed, a special arrangement of LC molecules is liable to cause some start-up problems, and ability to maintain uniformity in the manufacturing process for solving the start-up problems becomes a new difficult question in the display industry
Due to the higher technical threshold and existing patent monopoly about FFS mode LCD devices and IPS mode LCD devices being formed, using FFS and IPS display technologies requires of higher costs.
What is needed, therefore, is an improved LCD device that can overcome the above-described problems.